Chapter 3 Lab Using $lookup, not all 747 variants are counted

Hi There,

I wonder if the solution is correct.

In the data the 747 is also noted as 744 (abbrevation for 747-400 model ?).
There are also 74M variant, maybe 742, 743 for the old Queen Of the Skies or 748 for the latest generation.

Using /74.|380/ in the regex returns much more routes (747 amazingly) and One World takes the lead.

There is also an issue with KLM airline that has is “KLM Royal Dutch Airlines” in the routes but only “KLM” in the air alliance, then does not JOIN in the lookup.

Good lab anyway… and good training.

Hi Romain, welcome to the community :wave:.
Please note that the lab asks you to:

Which alliance from air_alliances flies the most routes with either a Boeing 747 or an Airbus A380 (abbreviated 747 and 380 in air_routes)?

This means you only have to find airplanes having 747 & 380 in their name.

    $match: {
      airplane: /747|380/

will work accordingly.

In case you have any doubts, please feel free to reach out to us.

Thanks and Regards.
Sourabh Bagrecha,
Curriculum Services Engineer


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